

import 'package:english_words/english_words.dart';
import 'package:flutter/material.dart';

class RandomWords extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return new RandomWordsState();
  }
}

class RandomWordsState extends State<RandomWords> {
  final _wordPair = <WordPair>[];
  final _saved = Set<WordPair>();

  final _fontStyle = const TextStyle(fontSize: 18.0);

  @override
  Widget build(BuildContext context) {
//    final wordPair = new WordPair.random();
//    return new Text(wordPair.asPascalCase);
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('listview'),
        actions: <Widget>[
          new IconButton(icon: new Icon(Icons.list), onPressed: _pushSaved)
        ],
      ),
      body: _buildSuggestion(),
    );
  }

  void _pushSaved() {
    Navigator.of(context).push(new MaterialPageRoute(builder: (context) {
      final tiles = _saved.map((pair) {
        return new ListTile(
          title: new Text(
            pair.asPascalCase,
            style: _fontStyle,
          ),
        );
      });
      final divided = ListTile.divideTiles(context: context, tiles: tiles).toList();

      return new Scaffold(
        appBar: new AppBar(
          title: new Text('我的收藏'),
        ),
        body: new ListView(children : divided),
      );
    }));
  }

  Widget _buildSuggestion() {
    return new ListView.builder(
        padding: const EdgeInsets.all(1.0),
        itemBuilder: (context, i) {
          if (i.isOdd) return Divider(color: Color.fromARGB(123, 255, 89, 0));
          //整除
          final index = i ~/ 2;
          if (index >= _wordPair.length) {
            _wordPair.addAll(generateWordPairs().take(10));
          }
          return _buildRow(_wordPair[index]);
        });
  }

  Widget _buildRow(WordPair pair) {
    final alreadySaved = _saved.contains(pair);
    return new ListTile(
      title: new Text(
        pair.asPascalCase,
        style: _fontStyle,
      ),
      trailing: new Icon(
        alreadySaved ? Icons.favorite : Icons.favorite_border,
        color: alreadySaved ? Colors.red : null,
      ),
      onTap: () {
        setState(() {
          if (alreadySaved) {
            _saved.remove(pair);
          } else {
            _saved.add(pair);
          }
        });
      },
    );
  }
}